> only that performance is a function of (among other things) these two mutually exclusive things.
You can have efficient communication even in culturally/racially/whatever diverse teams. Your original implication that somehow only homogeneity leads to more efficient communication is not quite correct.
Exactly. If I want to hire a group of people who are good at communicating I should focus on that aspect during the interview process rather than ensuring that they are all homogeneously white or brown or black or asian or men or women or catholic or middle class.
You can have efficient communication even in culturally/racially/whatever diverse teams. Your original implication that somehow only homogeneity leads to more efficient communication is not quite correct.